Funds are requested for the purchase of a fluorescence activated cell sorter. The cell sorter facility will provide an instrument as well as support services to meet the diverse research needs of the projected users. The primary users for this instrument are currently involved in a wide variety of programs concerning the regulation of growth and differentiation in normal and transformed cells. The addition of a fluorescence activated cell sorter to this institution would greatly benefit these programs as well as allow other approaches and areas of research to be undertaken.